Typically, mobile tracking and messaging antennas for mobile tracking and messaging systems, such as that used with Qualcomm Incorporated's OmniTRACS® system, are housed within a radome. A radome is an enclosed housing, usually made of a low-loss dielectric material that serves to protect antennas mounted on ground-based vehicles, ships, airplanes and the like without significantly altering the electrical performance of the enclosed antennas.
Transit buses and heavy industrial equipment having tracking and messaging systems are well suited for use with radomes. The dielectric material of the radome is usually made of a plastic material having a thickness on the order of the wavelength associated with an antenna used therewith.
Mobile tracking of equipment, such as industrial vehicles, can involve the Global Positioning System (GPS) which can be used to track vehicles using a number of low earth orbiting satellites.
FIG. 1 illustrates a three-dimensional perspective view of a prior art messaging and tracking antenna setup, including an antenna assembly, referenced herein as antenna communications unit (ACU) 2. ACU 2 in conjunction with circuitry, not shown, is a mobile transceiver. The ACU, when in installed in vehicles, such as trucks, allows two-way communication between drivers and logistic centers. GPS patch antenna 4, mounted to ground plane 5, provides reception of GPS signals which, for instance, allow truck systems controllers to know the location of a truck and its cargo. Patch antenna 4 and ground plane 5 are disposed on cast aluminum base 6 covered by radome 8. Base 6 of ACU 2 can be mounted to a vehicle (e.g., tractor cab). Radome 8 can be attached to base 6 preferably a using v-clamp. Rotating messaging antenna 10 which is well-suited for digital communications involving geostationary satellites, particularly involving code division multiple access (CDMA), is rotatable on pedestal 11 about axis 12 through radome 8 in a plane between peak 14 of radome 8 and base 6. Antenna 10 of FIG. 2 is illustrated as a horn antenna. A system of this type can, for example, use an uplink (transmit) frequency band of 14.0-14.5 GHz while the downlink (receive) frequencies range from 11.7-12.2 GHz. In an effort to improve satellite communications, antenna 10 rotates toward a satellite in connection with communication therewith.
While the messaging antenna is capable of movement to increase transmission and reception signal strength, the GPS antenna is stationary. In order to optimize GPS performance, it is desirable to locate the GPS antenna in clear line of sight to the GPS satellite constellation.
A method and apparatus for improving the GPS satellite reception is needed.
Applicable reference numerals have been carried forward.